Powertrain, generic (extended)

P238F Water in Fuel Condition - Sensor B

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P238F is no wiring fault: it states that water-in-fuel sensor B has detected water, meaning the separator at that point has collected enough to bridge the probe. Ram's 2022 heavy-duty pickups (2500 to 5500) are covered by Stellantis case S2214000004, which keeps it apart from the circuit code P238D: with P238F stored, the filter on the frame has to be emptied completely and the fuel tested for water before any electrical diagnosis. For sensor A the equivalent is P2269, which Ram's 2025–26 Cummins trucks report with the MIL. Water in diesel fuel damages high-pressure pumps and injectors and promotes microbial growth, so drain promptly, find the source (tank, fuel station, condensation) and replace the filter if needed.

Likely causes

Water collected in the chassis filter separator
Fuel contaminated with water from tank or filling station
Separator drained incompletely after an earlier warning

Symptoms

  • Water-in-fuel lamp or message on
  • Rough running or power loss if water reaches the injection system
  • MIL on some vehicles

Repair estimate

DifficultyEasyDIY possible
Parts and labour€0–200
Time0.2–1 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

water in fuel sensor bfuel filter housing b

Related codes

P238DP238AP2269

References: static.nhtsa.gov, static.nhtsa.gov, en.wikipedia.org.